1. Field of the Invention
The present invention relates to a resistor for detecting current, and the resistor uses metal plate as resistance body.
2. Description of the Related Art
In the past, a resistor that uses metal plate such as Ni—Cr system alloys as resistance body for current detection is known. For instance, in a case of minute size of 1005 size (1.0 mm×0.5 mm) etc., the resistor can be formed by piercing process etc. from a large size metal plate material that can produce a lot of pieces. In this case, because it is not possible to trim resistance value of the resistor at the stage of piercing processing of the metal plate material, it is necessary to trim one by one to desired resistance value in accuracy after making it to pieces by piercing processing etc.
In the field of resistor for current detection usage, there is a problem that causes inductance element to the resistor by trimming method of forming trim cut by laser trimming etc., which is used for usual chip resistor etc. Then, it has been proposed a trimming method that does not cause any inductance element by cutting resistance body in parallel to electrical current direction thereof (Japanese laid-open patent publication 2002-57009).
However, since each resistance body is not independent on the metal plate material of large size, it is difficult to make trimming and it is necessary to make trimming one by one after making it pieces from large size metal plate. There is a problem that this work becomes troublesome and a factor of cost increasing. Then, by forming accurately an insulation layer on inter-electrode with thick film patterning, and providing accurate electrode positions, and by finishing up size of resistance body in high accuracy, a manufacturing method of a resistor, which enables trimming unnecessary, is proposed (Japanese laid-open patent publication 2004-63503).